Dry decalcomania

ABSTRACT

A PRESSURE-SENSITIVE DECALCOMANIA IS FORMED OF A SUPPORT SHEET CONTAINING A PLURALITY OF INDICIA WITH AN ADHESIVE COATING COVERING THE INDICIA AND THE ADJACENT SURFACE OF THE SUPPORT SHEET. SELECTED SOLVENTS ARE EMPLOYED IN THE ADHESIVE COATING FOR TRANSFERRING THE INDICIA TO A RECEIVING SURFACE WHILE RETAINING THE ADHESIVE COATING SURROUNDING THE TRANSFERRED INDICIA ON THE SUPPORT SHEET.   D R A W I N G

June 1973 R. TORDJMAN 3,741,787

DRYIDECALOOMANIA v Filed June 8, 1971 '1 r r 4 3 Z 2a 1/ Y 2d INVENTORROGER TORDJ'MAN ma N??? United States Patent ice 3,741,787 DRYDECALCOMANIA Roger Tordjman, 78 La Calle, Saint Cloud, FranceContinuation-impart of abandoned application Ser. No.

ABSTRACT OF THE DISCLOSURE A pressure-sensitive decalcomania is formedof a support sheet containing a plurality of indicia with an adhesivecoating covering the indicia and the adjacent surface of the supportsheet. Selected solvents are employed in the adhesive coating fortransferring the indicia to a receiving surface while retaining theadhesive coating surrounding the transferred indicia on the supportsheet.

This is a continuation-in-part application of Ser. N0- 785,720 filedDec. 20, 1968, now abandoned.

SUMMARY OF THE INVENTION The present invention relates to drydecalcomanias which do not require either water or heat for transfer toa. receiving surface and, more particularly, to pressuresensitivedecalcomanias employing an adhesive coating containing two differentsolvents which assist in the transfer of indicia from a support sheet tothe receiving surface.

t Preferably, the support sheet is transparent or translucent and mayhave a mat or shiny finish on one or both of its faces. On one of itssurfaces, which is nonporous, a plurality of linked indicia, such asletters, numbers, symbols and the like, are deposited by a printingprocess, for example, offset, typography, seriography or heliogravureprocesses, and a pressure-sensitive adhesive coating is applied to theindicia and to the surface of the support sheet about the indicia.

Since, it is not practical to apply the adhesive coating only on thesurfaceof the indicia, the coating is applied to the entire surface ofthe support sheet. Accordingly, it is necessary that the adhesivecoating adhering directly to the non-porous surface of the support sheetbe retained on the sheet at the time anindicia or number of indicia istransferred to a receiving surface. It can be appreciated that thetransfer of additional adhesive coating to the receiving surface caninterfere with its appearance or can have a tendency to collect dustabout the periphery of the indicia."

When not being used for transferring indicia to a receiving surface, aprotective sheet is applied to the surface of the support sheetcontaining the indicia to prevent any accidental transfer of theindicia. A protective sheet having a surface treated with silicon iseffective forthis purose. g p To avoid transfer of the adhesive coatingit has-been found to bepreferable-to use a'material which doesnotprovide a sticky surface to the receiving surface, yet has a high degreeof cohesiveness and a good bond with the .supportsheet. I

15 Claims Patented June 26, 1973 In previously known methods oftransferring dry decalcomanias, the indicia have been removed by bendingthe support sheet, or alternatively, by providing a strong adhesive onthe outer surface of the indicia. However these two transfer methodshave their drawbacks, the first one risks damage to the indicia whenthey are bent at the same time that the support sheet is bent, and thesecond one risks accidental transfer of the indicia from the supportsheet.

Therefore, it is a primary object of the invention to overcome thedrawbacks previously experienced in the pressure sensitive transfer ofdecalcomanias and to provide a decalcomania which can be easily handledand transferred.

Another important object of the invention is to provide an adhesivecoating for the transfer of the indicia to a receiving surface whichembodies certain materials capable of assisting in the transfer of theindicia while maintaining the remainder of the coating on the supportsheet.

Therefore, the invention provides improvements in the transfer ofpressure-sensitive decalcomanias from a support sheet to a receivingsurface by providing an adhesive coating over a non-porous surface ofthe support sheet containing the indicia with the adhesive employedassisting in the removal of the indicia from the support sheet due to aphenomenon of migration effected by solvents contained within theadhesive.

In the formation of sheets of dry decalcomanias, in accordance with theinvention, a sheet, preferably formed of a transparent or translucentplastic material, is imprinted on a non-porous surface thereof with aplurality of indicia using a printing material such as ink or the likewhich has a low degree of adhesion or mechanical bond to the supportsheet and has practically no chemical action with the support sheet. Themolecules of the printing ink have an electro-chemioal charge of acertain polarity. In a polar liquid the electrical center of gravityfalls outside the mechanical center of gravity. The negative charge isfarther away from the core. With respect to electro-chemical charges ina material, reference is made to fTheory of Electric Polarisation, 1952C. J. F. Bottcher, and Adhesion and Cohesion 1962 Philip Weis, page 3(Elsevier Publishing Company). After the indicia are deposited on thesheet, a pressure-sensitive adhesive substance is coated onto the sheetcovering all of the indicia and the adjacent surfaces of the sheet. Theadhesive contains at least two solvents, one of which has anelectro-chemical charge opposite in polarity to that of theelectro-chemical charge of the printing material used in placing theindicia on the support sheet and, the other solvent is not provided witha charge which attracts it to the molecules in the printing ink. Thefirst solvent, due to the opposite character of its charge relative tothe charge on the printing material or ink forming the indicia, formsabond about the individual molecules of the printing substance andprovides the body of material forming the indicia with a certain degreeof porosity. Due to this porosity, the second solvent, since it is notattracted to the charges molecules of the printing material, infiltratesthrough the indicia and comes into contact with the surface of thesupport sheet under the indicia. The presence of the second solvent atthe interface between the indicia and the support-sheet effects areduction in the adhesion of the indicia to the sheet, because itcontains a charge of the same character as the charge of the ink, sothat the indicia which is mechanically but not chemically bonded to thesupport sheet can be easily transferred to a receiving surface by theapplication of pressure on the opposite surface of the support sheet.For providing an effective adhesive coating, the materials used to formthe coating are specifically selected to aid in the separation of theindicia from the support sheet and to afford a shearing of the adhesivecoating at the lateral peripheral boundaries of the indicia.

The migrating solvents, that is, the solvents passing through theindicia may contain other elements of materials for the followingpurposes.

(a) To reduce the adhesion of the indicia to the surface of the supportsheet. It is possible to accentuate the proportion of the migratingsolvent, or solvents, to obtain a total detachment of the indicia fromthe support sheet. Where the detachment of the indicia is complete andthe layer of the adhesive coating is very thin over the indicia, iteasily breaks around the peripheral boundary of the indicia permittingit to be completely separated from the support sheet. In somecircumstances, this effect may be desirable, however, it does provide aconsiderable danger of accidentally transferring the indicia from thesupport sheet.

To prevent the likelihood of accidental transfer, the amount of thedifferent solvents should be carefully proportioned whereby the bondingof the indicia to the support sheet is broken, but, the cohesiveness ofthe adhesive coating at the edges of the indicia is not sheared and, asa result, the indicia is retained on the support sheet.

(b) Where it is advantageous to do so, the migrating solvents may alsoinclude certain deactivating elements. These deactivating elements caneffect a change in the adhesive quality of the coating covering theindici-a and provide it with a greater adhesive ability.

(c) Other elements may be incorporated in the migrating solvent toprovide an effect on the surface of the indicia contacting the supportsheet, that is, the outer surface of the indicia when it is transferredto a receiving surface. Therefore, a matting agent included 'in theadhesive material can provide a mat appearance to the surface of theindicia when the material infiltrates through the indicia to the surfaceof the support sheet.

When the support sheet has shiny surfaces, the effect on the mattingagent can be particularly noted since it infiltrates through the indiciaand becomes apparent through the surface of the support sheet at theinterface with the indicia. Y

The various effects just described, attainable by mixin certain elementswith the solvent which migrates through the indicia, can be obtainedeither separately or in combination by using the proper elements.

The following is a listing of the characteristics of the various membersor parts which combine to form a dry decalcomania:

SUPPORT SHEET The support sheet has a non-porous surface on which theindicia are deposited and is formed of a material, preferablytransparent or translucent, for affording good registration in thetransfer of the indicia to a receiving surface. The surfaces of thesupport sheet can be dull on one or both sides or polished on one orboth sides, while the thickness of the sheet can vary Within Wide limitsranging between 0.0010 to 0.010 inch."

To prevent the indicia from adhering strongly to the surface of thesupport sheet, it is important that the solvents used during theplacement of the. indicia on the support sheet have the weakest possibleinteraction with its surface.

THE INDICIA The indicia are formed of a substance having ,good physicaldrying properties which form, after the evaporation of the solvents, aflexible film-like member on the support sheet. The indicia can beapplied by any known method of printing or coating.

The printing materials employed in forming the indicia should form aweak or limited bond with the surface of the support sheet, therefore,it is not recommended that substances be employed in forming the indiciawhich would tend to adhere strongly to the support sheet. When thesolvents in the subtsance forming the indicia have evaporated, aflexible film-like member is formed on the support surface which can betransferred as a unit to a receiving surface. In forming the indicia onthe support surface, the substance used should be sensitive to theaction of certain solvents contained in the adhesive material used asthe coating since this characteristic is indispensible where thephenomenon of migration is employed.

The adhesive solution applied to the outer surfaces of the indicia onthe support surface as well as to the remaining surface thereof isdiluted with a combination of at least two solvents:

TYPE I SOLVENT The first or type I solvent carries an electro-chemicalcharge opposite to that impressed on the indicia and forms a film whichcovers or encloses and is, due to the opposite nature of theelectrostatic charge, bonded to the indicia. The interaction of thefirst solvent and the indicia cause a swelling and the indicia develop adegree of p0- rosity which permits the infiltration of the second ortype II solvents through the indicia. As the type I solventa ketoneand/or glycol can be used.

TYPE II SOLVENT The second or type II solvent is not attracted to thesubstance forming the indicia and thus it is possible for it toinfiltrate through the indicia to the interface shared with the supportsheet. The second solvent can include a small percentage of a solventwhich is attracted to the surface of the support sheet by reason of thepressure of opposite electro-chemical charges in the solvent and in thesupport sheet to facilitate the migration of the solvent through theindicia. However, the percentage of this additional solvent must belimited since too great an infiltration of the second solvent throughthe indicia would result in totally detaching it from the support sheet.

The type II solvents can serve as a vehicle or carrier for otherelements mixed into the adhesive solution, and with which they aresoluble. As the type II solvent aliphatic and aromatic compounds can beused.

By employing these different elements carried by the second solvent, itis possible to achieve different effects, based on the type of elementsused, such as'providing a mat effect for the interface surface of theindicia, improving the adhesive character of the coating with thereceiving surface, and affording total detachment of the indici from thesupport sheet, to name a few.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

BRIEF DESCRIPTION THE DRAWINGS the support sheet and deposited on areceiving-surface; and

FIG. 4 is a partial sectional view illustrating the support surfacecontaining several indicia encircled by the adhesive coating.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, an indicia 2is shown imprinted upon a nonporous support surface 1, and while onlyone indicia is shown, it will be appreciated that the support-surfacecan contain a great number of indicia in a relatively closely spacedarrangement. The material forming the indicia is mechanically bonded tothe non-porous support-surface, but it has practically no chemicalaction with the support sheet. After the indicia are formed on thesupport sheet, the adhesive solution 3 (FIG. 2) is deposited across theentire surface of the support sheet and a relatively thin layer 3' issuperposed on the face of the indicia directed outwardly from thesupport sheet.

Infiltration of the solvents of the adhesive solution has caused theformation of a film as indicated at 4 between the support sheet 1 andthe indicia 2.

In FIG. 3, the support sheet 1 is shown overlying a receiving surface10. When the indicia 2 is being transferred from the support sheet 1 tothe receiving surface 10, the support sheet or at least the adhesivecoating 3, 3' is in contact with the receiving surface 10. By applying apressure force in the direction of the arrows f, the adhesive coating 3on the outer surface of the indicia is bonded to the receiving surfaceand the infiltration of the second solvent in the adhesive coating hasprovided a surface 4 of reduced attachment between the interface of thesupport sheet and the indicia so that after the pressure has beenapplied to the support sheet, the indicia adheres to the receivingsurface and separates both from the surface 4 of the support sheet andfrom the adjoining coating 3 on the support sheet.

The ability of the indicia to separate from the enclosing portions ofthe adhesive coating disposed about its peripheral boundaries isexplained due to the high degree of adhesion of the coating 3 to thesurface of the support sheet while within the boundaries of the indicia,the solvents have combined to provide a separation of the indicia fromthe opposed surface of the support sheet. The reduced thickness of thecoating 3' over the indicia 2 and the infiltration of the solventsthrough the indicia provide the required effect for achieving a cleanshear or rupture action between the different portions of the adhesivecoating 3, 3'.

In FIG. 4, the manner in which the different solvents within theadhesive coating 3 act is shown in a schematic arrangement in which thehatched parts 2a designate the molecules of the indicia and the opencircles 5 define the molecules of the first or type I solvent which areattracted and bonded to the molecules of the indicia. Disposedoutwardl'y" of and between the molecules and the molecules of'the'firstsolvent 5 are molecules 6, shown by solid circles which infiltratebetween the molecules 2a of the indicia and contact the surface orinterface the indicia and the support sheet 1. The openings between themolecules 2a of the indicia indicate the porosity afforded by theinteraction of the-indicia and the first solvent which permits thesecond or type II solvent to pass into contacting relationship with thesurface of the support sheet.

THE ADHESIVE SOLUTION After it has dried, the adhesive solutioncoated onthe surface of the support sheet 1 and on the indicia 2 provides apressure-sensitive coating for the subsequent transfer of the indicia toa receiving surface 10... H

In the selection of theadhesive materials, it isnece's'; sary to usematerials which have. a good adhesion to; the surface of the supportsheet. It is desirable that the pressure-sensitive adhesive be more.stronglybonded' to the surface of the support sheet 1 than to thesurface of a receiving member 10, and it is preferable if the adhesivematerial has a relatively low sticking power so that in the step oftransferring the indicia to the receiving surface 10, the remainder ofthe adhesive coating 3 remains on the support sheet and is nottransferred over to the receiving surface.

Another factor to be considered is the cohesiveness of the coating 3,3', which must be sufficient to hold the indicia on the support sheetyet permit the shear between the coating 3 on the sheet and the coating3' on theindicia. For this reason, the use of wax in large proportionsin the adhesive solution is to be avoided. However, if the cohesiveforce of the adhesive coating is not carefully balanced and the cohesiveforce between the different parts of the coating 3, 3' is great it maynot be possible to effect a proper transfer of the indicia from thesupport sheet 1 to the receiving surface 10.

The cohesive character of the coating 3, 3 should be such that it willpermit thedetachment of the indicia 2 from the support sheet 1 by ashearing action about the laterally peripheral boundaries of theindicia. The shearing effect can be facilitated about the edges of theindicia by accenting the'detachment of the indicia by means of thephenomenon of migration.

An effective shearing of the adhesive coating 3 from that portion of thecoating 3' on the indicia is possible by providing a substantialinfiltration of the second solvent through the indicia to the surface ofthe support sheet 1. However, care must be taken to prevent theaccidental transfer of the indicia from the support sheet.

It will be appreciated that the role of the adhesive coating is toretain the indicia on the support sheet until it is transferred by apressure action to a receiving surface and then it is important for theadhesive coating to separate in a clean line about the lateral peripheryof the indicia.

The duty of the adhesive layer in the present invention actually is, inthe first part to retain on the support sheet the indicia released fromthe surface of the support sheet by the infiltration of the solventsand, in the second part to attract the indicia and secure it against thereceiving surface.

To avoid any accidental transfer of the indicia, it is recommended thatthe adhesive coating have a relatively dry, non-sticky nature on itssurface exposed to the receiving surface.

When the indicia 2 is applied to the support sheet 1, it has a certaindegree of bonding to the support surface prior to the coating with theadhesive solution. When the adhesive solution is deposited on thesurface of the support sheet, the infiltration of the type II or secondsolvent through the indicia effects a loosening of the bond between theindicia and the support sheet at the interface surface 4. It is notconsidered good practice to employ an adhesive having a high adhesive orsticky nature, but it should be capable of attaching and fixing theindicia to the receiving surface in the transfer operation. The adhesive nature of the coating should be proportional to the ability ofthe indicia to adhere to the support sheet. Accordingly, the greater theadherence of the indicia to the support sheet, the greater should be theadhesion between the indicia and the receiving surface by means of theadhesive.

By employing the present invention, it is possible to achieve transferof indicia from a support sheet by utilizing adhesives which have a lowdegree of adhesiveness and as a result improves the utilization of theproduct.

The following are examples of practical application of the inventionindicating the various materials and substances used in forming thepressure-sensitive decalcomanias, inthese examples of the-ketones andglycols are the-type Isolvents and the aliphatic and aromatic compoundsarethe type II solvents.

(I) Case of a support constituted by a sheet of polyvinyl chloride (a)Composition of the indicia: Solution of polystyrol in an aromaticsolvent with a boiling range of 160 to 190 C.; in order to obtain ablack indicia the solution can be colored by a pigment constituted bycarbon black.

(b) Composition by weight, of the adhesive:

Polyvinyl ether with low viscosity 3.2. Polyvinyl ether with highviscosity 5.0 Wax with polyethylene base, with low molecular weight 0.4Silica powder 2.6 Aliphatic hydrocarbon with a boiling range of 155 to195 C., e.g. white spirit 50.00 Aliphatic hydrocarbon with a boilingrange of 66- 70 C. 20.00 Glycolic ether with a boiling range of 132136C.,

e.g. ethylene glycol monomethyl ether 9.9 Cyclohexanone 8.9

(II) Case of a support constituted by a sheet of polystyrene (a)Composition of the indicia: Ink with plastified nitrocellulose base,colored with carbon black in the case of a black ink.

(b) Composition, by weight, of the adhesive:

It will be appreciated that the examples set forth above are provided byway of explanation and not limitation.

What is claimed is:

1. A dry decalcomania comprising a support sheet, at least one indiciabeing formed of a printing ink and deposited on said support sheet, saidprinting ink having a mechanical bond to said support sheet butpractically no chemical action with said support sheet, and apressuresensitive adhesive substance being applied in the form of asolution to and forming a coating on said support sheet bearing saidindicia, said adhesive coating completely covering said indicia andextending laterally therefrom over said support sheet, said printing inkhaving mole cules with electrochemical charges of a given polarity, saidsolution of the adhesive substance comprising at least one solvent withelectrochemical charges of a polarity opposite to the polarity of thecharges of the printing ink whereby said first solvent is attracted tothe printing ink forming said indicia and adheres about the printing inkwhile imparting to it a degree of porosity, said solution of theadhesive substance comprising at least one further solvent the moleculesof which do not comprise any electrochemical charges of a polarityopposite to the polarity of the charges in the printing ink, wherebysaid second solvent infiltrates through said indicia due to the degreeof porosity achieved by its interaction with said first solvent andeffects a reduction in the adhesion of said indicia to said supportsheet.

2. A decalcomania, as set forth in claim 1, wherein said support sheetis formed of a material of such a nature that it is possible to seethrough said sheet from the surface opposite-the one bearing the indiciafor obtaining proper registration in transferring said indicia to areceiving surface.

3. A decalcomania, as set forth in claim 2, wherein said support sheethas a thickness in the range of 0.010 to 0.001 inch.

4. A decalcomania, as set forth in claim 3, wherein said sheet is formedby one of polyvinyl chloride or polystyrene.

5. A decalcomania, as set forth in claim 1, wherein the printing ink ofsaid indicia comprises a substance be ing arranged to dry on saidsupport sheet to provide said indicia with a flexible film-like formcapable of being removed as a unit from said support sheet.

6. A decalcomania, as set forth in claim 5, wherein said substancecomprises a solution of polystyrol in an aromatic solvent having a highboiling point.

7. A decalcomania, as set forth in claim 5, wherein said substancecomprises an ink with a plasticized nitrocellulose base.

8. A decalcomania, as set forth in claim 1, wherein said adhesivecoating in contact with said support sheet has a greater adhesive bondwith said support sheet than with a receiving sunface whereby thetransfer of the adhesivecoated indicia from the support sheet to thereceiving surface is effected while the adjacent adhesive coatingremains secured to the support sheet.

9. A decalcomania, as set forth in claim 8, wherein said second solventincludes a small amount of a solvent having an attraction for saidsurface of said support sheet for facilitating the migration of saidsecond solvent through said indicia.

10. A decalcomania, as set forth in claim 8, wherein said adhesivesubstance contains agents mixed with said first and second solvents forincreasing the adhesiveness of said indicia to said receiving surface.

11. A decalcomania, as set forth in claim 10, wherein an agent isincluded in said adhesive substance for eifecting a mat-finish on theoutwardly facing surface of said indicia when transferred to a receivingsurface.

12. A decalcomania, as set forth in claim 1, wherein said adhesivecoating has a composition by weight as follows:

13. A decalcomania, as set forth in claim 1, wherein the composition byweight of the adhesive coating is as follows:

Polyvinyl either with low viscosity 3.0 Polyvinyl ether with highviscosity 5.6 Wax with polyethylene base with low molecular weight 0.4Silica powder 3.0 Aliphatic hydrocarbon with a boiling range of C. 54.0Aliphatic hydrocarbon with a boiling range of 66- 70 C. 22.0 Glycolicother with a boiling range of 132- Total 100.00

14. A dry decalcomania for transfer without the use of Water or heat,comprising a support sheet having a non-porous surface formed by atleast a coating of a plastic material thereon, at least one indiciabeing formed of a printing ink having an electrochemical charge anddeposited on said support sheet, said printing ink having a mechanicalbond to but practically no chemical action with said support sheet, anda pressure-sensitive adhesive substance being applied in the form of asolution to and forming a coating on said support sheet bearing saidindicia, said adhesive coating completely covering said indicia andextending laterally therefrom over said support sheet, said printing inkhaving molecules bearing electrochemical charges of a given polarity,said first solution of the adhesive substance containing at least afirst solvent consisting of at least one of a ketone and a glycolbearing an electrochemical charge of a polarity opposite to the polarityof the electrochemical charge on the printing ink forming said indiciaand adheres about the molecules of the printing ink imparting theindicia wth a degree of porosity, said solution of the adhesivesubstance containing at least a second solvent consisting of at leastone of an aliphatic and an aromatic compound which does not comprise anelectrochemical charge of a polarity opposite to the polarity of thecharge on the printing ink,

whereby said second solvent infiltrates through said indicia due to thedegree of porosity achieved by the interaction of said first solventtherewith and effects a reduction in the adhesion of said indicia tosaid support sheet.

15. A dry decalcornania, as set forth in claim 14, characterized thereinthat said first solvent is formed of at least one glycolic ether with aboiling range of 132-136 C. and cyclohexanone and said second solventconsists at least of one of an aliphatic hydrocarbon with a boilingrange of -195 C. and an aliphatic hydrocarbon with a boiling range of66-70 C.

References Cited UNITED STATES PATENTS 3,298,850 1/1967 Reed et a1.117--3.1 3,212,913 10/1965 Mackenzie 117-3.1 3,459,626 8/1969 Morgan117-3.1X

WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant ExaminerU.S. Cl. X.R. 156-234; 161-406

